Charles e



' (NoModeL) O. E. SCRIBNER. TELEPHONE. v No. 571,907. Patented N0v,24,1896. J I 3:

A E IQ Wz'frzesaew F 1720672507 THE uunms PETERS ca., wisumcron. n. c.

UNITED STATES PATENT OF ICE.

CHARLES SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY,- OF SAME PLACE.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 571,907, dated November 24, 1896. Application filed February '7, 1898. Serial No. 461,389. (No model.)

To all whom it may concern..-

Be it known that I, CHARLES E. SCRIBNER, a citizen of the United States, residing at Chic-ago, in the county of- Cook and State of Illinois, have invented a certain new and useful Improvement in Telephones, (Case N o. 320,) of 'which the following is afull, clear, concise,

and exact description, reference'being had to the accompanying drawing, forming a part of this specification.

' My invention relates'toelectric speakingtelephones. Its object is to produce a simple,

.compact, and efficient electromagnetic telephone-receiver,- being more particularly dis rected to providing new means for securing a normal constant magnetization of the core of theelectromagnet.

As is well known in the artto which my invention pertains, it is desirable that the electromagnet which acts .upon the diaphragm of the telephone should have a certain amount of constant magnetization in which fluctuations may be produced by the varying magnetizing forces of the telephonic currents.

This arises from the fact that unmagnetized or very feebly magnetized iron is much less responsive to feeble fluctuations of the mag-l netizing force, .such as that of the feeble telephonic currents, than iron which already proaching semisaturation.

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possesses a considerable magnetization apconstant magnetization of the core of the telephone electromagnet has been produced either bya permanent-magnet in whose field the core of the electromagnet hasbeen placed or by an auxiliary coil upon theelectromagstance the eflici'ency of v the instrument is somewhat reduced by the inferior susceptibility of the steel which constitutes a part of the magnetic circuit of the telephone-elec tromagnet and in the latter instance by'the opposing effect of the currents which are induced in the closed-local-battery circuit by the undulating telephonic current. Inboth cases, also, the bulk of'theinstrnments is un-.

necessarily increased. p

In my invention I provide a simple electromagnet, adapted to act upon the diaphragm,

Heretofo're thisnet, in circuit with a battery. 1 In the first inv and. a retardation-coil in different parallel branches of the line-circuit, a battery being included in one of the branches. The two parallel branches form a closed local circuit including the telephone-electromagnet and a battery. A continuous current thusfiows from] the battery through the .local circuit, finding unobstructed passage through the re tardation-coil, While the telephonic currents are largely or almostwholly prevented from passing through that branch of the 11116-011- cuit by the high impedance of the retarda-' tion-coil; or, in other words, the rapidvariations of the difference-of potential between I the points of junction ofthe branch circuits produce variations in the current through that branch containing the telephone-magnet, but are prevented from producing any perceptible variations in the current through the retalrdation-coil. The telephone-electror magnet is thus given a normal constant magnetization, which is varied .or caused to -fiuctuate by theundulations ofthe telephonic" This normal constant magnetiza currents. I tion may be adjusted to any suitable amount by adjusting the strength of the normal current in the local circuit. By this arrangement I am enabled to employ a small elect-r0.- magnet of the greatest attainable permeability and to adjust it tothe maximum sensitiveness to feeble fluctuations of the magnetizing force, and thus to produce a very efficient instrument.

forth in connection therewith. Ihave shown two telephone sets, each com- My invention is illustrated in the aceomv panying drawing and may be more fully set risin a tele hone-receiver constructed and P. a P

arranged in accordance with my invention, a microphone, and the induction-coil thereof, the two telephone sets being connected together by a telephone-line.

An ordinary long-distance transmitter dis shown connected in circuit with a battery I) and the primary helix. of an induction coil 0, whose secondary helix is included in the linecircuit (2 d". The telephone-receiver e is shown in longitudinal central section. It comprises a tubular electromagnete", the

telephone-diaphragm e 'opposite the polesof the magnet, and the .inclosing case 6 which serves also to hold the parts in place.

The electromagnet e is eonnect-edin one branchfof the line-circuit d d. A retardation-coil g is connected in another parallel branch g of the line-circuit, as described. The battery I), which serves as the micro-- phone-battery, is included in the branch '9, containing the retardation-coil The linecircuit may thus be traced from the line-wire (I through the secondaryhelix of inductiom cell c to one terminal of the branch circuits f g At that point it divides, and one circuit may be traced through the conductor f and through the telephone-receiver e to the other side, d, of the line-circuit. The other branch ci rcuitmay be traced through the conductor 9 retardation-coil g, and battery I) to 'the othersi'de, d, of theline-circuit. The battery b is bythis means provided with a local circult through the branch g and the retardanon-coil g to the branch f, thence through the telephone-receiver e to the other side of the branch f, and thence through the corresponding portion of the branch 'g',returning to battery b. The magnet e is thus energized by a continuous current from battery I), which current is also rendered constant by the retardation-coil g, whose impedance, prevents any sudden fluctuations of the current. At

the same time the undulating telephonic cur-- r nt from the line-circuit d vd finds circuit only through the -branch f containing the telephone receiver, being prevented from passing through the branch g by the impe-,.

dance of retardation-'coilg.

Having described my invention, what. I claim as new, and desire to secure by Letters Patent, is-- 1. "The combination with the electromagnet of atelephone-receiver, of an electromagnetic coil not one of the telephone-coils, and circuits connecting the telephone-receiver and the said electromagnetic coil in different parallel branches of a line-circuit; and a source of electricity in one of said branches, whereby the battery and telephone-coil are included in a local circuit and the passage of telephonic currents through -the battery is prevented by the impedance-coil, substantially as described.

2. The combination with the coil of a telephone, included in one branch of a circuit, of a separate retardation or impedance coil included in a second branch, and a source of electricity in one of said branches, whereby the battery and telephone-coil are included in a local circuit and the passage of telephonic cnrrents'through the battery is prevented by the impedance-coil; substantially as described.

In witness whereof I hereunto subscribe my name this 6th day of January, A. D. 1893.

' CHARLES E. SORIBNER. \Vitnesses ELLA EDLER, A. P. Bnnuoerr. 

